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Abstract
This review discusses our studies on molecular mechanisms of acrylamide neurotoxicity by using the rat pheochromocytoma (PC12) cell line. The results showed that: a) acrylamide altered the gross morphology of PC12 cells; b) acrylamide induced neurofilament accumulation in PC12 cells; c) the effects of acrylamide on PC12 cells are consistent with its neurotoxicity in vivo; d) acrylamide stimulated neurofilament protein synthesis in PC12 cells; e) acrylamide did not act via nerve growth factor (NGF) receptor gp140trk to regulate neurofilament synthesis in PC12 cells; f) dexamethasone antagonised NGF and/or acrylamide-induced neurofilament protein synthesis and expression; and g) acrylamide differentially regulated the mRNA levels of three neurofilament subunit genes in PC12 cells. These molecular studies provide the first evidence that: a) there are distinctive and convergent signalling pathways for NGF-regulated and acrylamide-regulated neurofilament expression; b) acrylamide may differentially regulate the expression of each subunit, resulting in aberrant accumulation of neurofilament proteins; and c) there is a dexamethasone-sensitive signalling step common to NGF and acrylamide. These results could partially explain the mechanisms of neurofilament accumulation in distal axonal swellings, a pathognomonic feature of acrylamide neurotoxicity.
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Affiliation(s)
- Weiquan W. Lin
- Laboratory of Neurotoxicology, Department of Pharmacology, Duke University Medical Centre, P.O. Box 3813, Durham, NC 27710, USA
| | - Larry R. Johnson
- Cytec Industries, 5 Garret Mountain Plaza, West Paterson, NJ 07424, USA
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Collí-Dulá RC, Friedman MA, Hansen B, Denslow ND. Transcriptomics analysis and hormonal changes of male and female neonatal rats treated chronically with a low dose of acrylamide in their drinking water. Toxicol Rep 2016; 3:414-426. [PMID: 28959563 PMCID: PMC5615912 DOI: 10.1016/j.toxrep.2016.03.009] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2016] [Revised: 03/02/2016] [Accepted: 03/16/2016] [Indexed: 12/28/2022] Open
Abstract
Acrylamide is known to produce follicular cell tumors of the thyroid in rats. RccHan Wistar rats were exposed in utero to a carcinogenic dose of acrylamide (3 mg/Kg bw/day) from gestation day 6 to delivery and then through their drinking water to postnatal day 35. In order to identify potential mechanisms of carcinogenesis in the thyroid glands, we used a transcriptomics approach. Thyroid glands were collected from male pups at 10 PM and female pups at 10 AM or 10 PM in order to establish whether active exposure to acrylamide influenced gene expression patterns or pathways that could be related to carcinogenesis. While all animals exposed to acrylamide showed changes in expected target pathways related to carcinogenesis such as DNA repair, DNA replication, chromosome segregation, among others; animals that were sacrificed while actively drinking acrylamide-laced water during their active period at night showed increased changes in pathways related to oxidative stress, detoxification pathways, metabolism, and activation of checkpoint pathways, among others. In addition, thyroid hormones, triiodothyronine (T3) and thyroxine (T4), were increased in acrylamide-treated rats sampled at night, but not in quiescent animals when compared to controls. The data clearly indicate that time of day for sample collection is critical to identifying molecular pathways that are altered by the exposures. These results suggest that carcinogenesis in the thyroids of acrylamide treated rats may ensue from several different mechanisms such as hormonal changes and oxidative stress and not only from direct genotoxicity, as has been assumed to date.
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Key Words
- ADA, adenosine Deaminase
- ADRB2, adrenergic
- ASF1B, anti-Silencing Function 1B Histone Chaperone
- Acrylamide
- BRIP1, BRCA1 Interacting Protein C-Terminal Helicase 1
- BUB1B, BUB1 Mitotic Checkpoint Serine/Threonine Kinase B
- C1QTNF3, C1q and Tumor Necrosis Factor Related Protein 3
- C5, complement Component 5
- CALCR, calcitonin receptor
- CARD9, caspase recruitment domain family
- CCNA2, cyclin A2
- CCNG1, cyclin G1
- CD45, protein tyrosine phosphatase
- CD46, CD46 molecule
- CDC45, cell division cycle 45
- CDCA2, cell division cycle associated 2
- CDCA5, cell division cycle associated 5
- CENPT, centromere protein T
- CFB, complement factor B
- CGA, glycoprotein hormones
- CTLA4, cytotoxic T-lymphocyte-associated protein 4
- DAD1, defender against cell death 1
- DCTPP1, DCTP pyrophosphatase 1
- DNMT3A, DNA (cytosine-5-)-methyltransferase 3 alpha
- DUOX2, dual oxidase 2
- GCG, glucagon
- GCLC, glutamate-cysteine ligase
- GOLGA3, golgin A3
- GSTM1, glutathione S-transferase Mu 1
- GSTP1, glutathione S-transferase Pi 1
- HPSE, heparanase
- HSPA5, heat shock 70 kDa protein 5
- HSPB1, heat shock 27 KDa protein
- HSPB2, heat shock 27 kDa protein 2
- HSPH1, heat shock 105 kDa/110 kDa protein 1
- HTATIP2, HIV-1 tat interactive protein 2
- ID1, inhibitor of DNA binding 1
- IGF2, Insulin-like growth factor 2 (somatomedin A)
- IL1B, interleukin 1
- INHBA, inhibin
- IYD, iodotyrosine deiodinase
- KIF20B, kinesin family member 20B
- KIF22, kinesin family Member 22
- KLK1, kallikrein 1
- LAMA2, laminin, alpha 2
- MCM8, minichromosome maintenance complex component 8
- MIF, macrophage migration inhibitory factor
- MIS18A, MIS18 kinetochore protein A
- NDC80, NDC80 kinetochore complex component
- NPPC, natriuretic peptide precursor C
- NPY, neuropeptide
- NUBP1, nucleotide binding protein 1
- ORC1, origin recognition complex
- PDE3A, phosphodiesterase 3A
- PINK1, PTEN induced putative kinase 1
- PLCD1, phospholipase C
- PLK1, polo-like kinase 1
- POMC, proopiomelanocortin
- PRKAA2, protein kinase
- PRL, prolactin
- PRODH, proline dehydrogenase
- PTGIS, prostaglandin I2 (prostacyclin) synthase
- PTGS1, prostaglandin-endoperoxide synthase 1
- RAB5A, RAB5A
- RAN, ras-related nuclear protein
- RRM2, ribonucleotide reductase M2
- RccHan Wistar
- SCL5A5, solute carrier family 5 (sodium iodide symporter)
- SELP, selectin P (granule membrane protein 140 kDa
- SPAG8, sperm associated antigen 8
- TACC3, transforming
- TBCB, tubulin folding cofactor B
- TFRC, transferrin receptor
- TOP2A, topoisomerase (DNA) II alpha
- TPO, thyroid peroxidase
- TSHR, thyroid stimulating hormone receptor
- TSN, translin
- Thyroid
- Transcriptomics
- VWF, Von Willebrand Factor
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Affiliation(s)
- Reyna Cristina Collí-Dulá
- Department of Physiological Sciences and Center for Environmental and Human Toxicology, University of Florida, Gainesville, FL 32611, USA
| | | | - Benjamin Hansen
- Laboratory of Pharmacology and Toxicology, D-211134, Hamburg, Germany
| | - Nancy D Denslow
- Department of Physiological Sciences and Center for Environmental and Human Toxicology, University of Florida, Gainesville, FL 32611, USA
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Friedman MA, Zeiger E, Marroni DE, Sickles DW. Inhibition of rat testicular nuclear kinesins (krp2; KIFC5A) by acrylamide as a basis for establishing a genotoxicity threshold. J Agric Food Chem 2008; 56:6024-6030. [PMID: 18624434 DOI: 10.1021/jf703746f] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Acrylamide is a toxic substance that induces a variety of cellular responses including neurotoxicity, male reproductive toxicity, tumorigenicity, clastogenicity, and DNA alkylation. Evidence is provided that inhibition of the microtubule motor protein kinesin is responsible for acrylamide-induced clastogenicity and aneuploidy. Two kinesin motors, KIFC5A and KRP2, which are responsible for spindle assembly and disassembly of kinetochore MT, respectively, are inhibited by acrylamide. The inhibitory concentration for a response is below the levels shown to adversely affect the cytogenetic parameters. The relative contribution of these inhibitions compared to DNA alkylation is considered. The implications of inhibition of these kinesins as the site of action of acrylamide with regard to risk assessment are substantial as this event will have a threshold and a safe level of acrylamide can be determined.
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Affiliation(s)
- Marvin A Friedman
- Department of Pharmacology and Toxicology, University of Louisville School of Medicine, Louisville, Kentucky 40292, USA.
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Abstract
Acrylamide (AM), used in the manufacture of polyacrylamide and grouting agents, is produced during the cooking of foods. Workplace exposure to AM can occur through the dermal and inhalation routes. The objective of this study was to define the kinetics of elimination of AM and its metabolites following oral and dermal administration. This is the second part of a study in which metabolites and hemoglobin adducts of AM were determined in people (Fennell et al., 2005, Toxicol. Sci. 85, 447-459). (1,2,3-(13)C(3))AM was administered in an aqueous solution orally (single dose of 0.5, 1.0, or 3.0 mg/kg) or dermally (three daily doses of 3.0 mg/kg) to sterile male volunteers. Urine samples were collected at 0-2, 2-4, 4-8, 8-16, and 16-24 h following administration orally, or at 0-2, 2-4, 4-8, 8-16, and 16-24 h following each of three daily dermal doses. (13)C(3)-AM and its metabolites in urine, (13)C(3)-glycidamide, (13)C(3)-N-acetyl-S-(3-amino-3-oxopropyl)cysteine and its S-oxide, and (13)C(3)-N-acetyl-S-(3-amino-2-hydroxy-3-oxopropyl)cysteine, were quantitated using liquid chromatography-tandem mass spectrometry. The recovered urinary metabolites accounted for 45.6, 49.9, and 39.9% of a 0.5, 1.0, and 3.0 mg/kg oral dose (0-24 h), respectively, and for 4.5% of the dose after 3 mg/kg was administered daily for 3 days dermally (0-4 days). These results indicate that after oral administration AM is rapidly absorbed and eliminated. The half-life estimated for elimination of AM in urine was 3.1-3.5 h. After dermal administration, AM uptake is slow. This study indicated that skin provides a barrier that slows the absorption of AM, and results in limited systemic availability following dermal exposure to AM.
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Affiliation(s)
- Timothy R Fennell
- RTI International, Research Triangle Park, North Carolina 27709 UMDNJ, Newark, New Jersey 07103, USA.
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5
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Abstract
Acrylamide is metabolized by direct conjugation with glutathione or oxidation to glycidamide, which undergo further metabolism and are excreted in urine. In rats administered 3 mg/kg 1,2,3-13C3 acrylamide, 59% of the metabolites excreted in urine was from acrylamide-glutathione conjugation, whereas 25% and 16% were from two glycidamide-derived mercapturic acids. Glycidamide and dihydroxypropionamide were not detected at this dose level. The metabolism of acrylamide in humans was investigated in a controlled study with IRB approval, in which sterile male volunteers were administered 3 mg/kg 1,2,3-13C3 acrylamide orally. Urine was collected for 24 h after administration, and metabolites were analyzed by 13C NMR spectroscopy. At 24 h, urine contained 34% of the administered dose, and 75% of the metabolites were derived from direct conjugation of acrylamide with glautathione. Gycidamide, dihydroxypropionamide and one unidentified metabolite were also detected in urine. This study indicated differences in the metabolism of acrylamide between humans and rodents.
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Abstract
The present study assessed biochemical endpoints indicative of acrylamide toxicity in astrocyte cultures derived from neonatal rat pups. Given earlier reports on the possible ability of acrylamide to induce astrocytomas in the Fischer 344 rat, we performed studies in neonatal rat astrocyte cultures from the Fischer 344 to assess the ability of acrylamide to induce astrocytic proliferation. Measurements on astrocytic proliferation included [3H]-leucine incorporation, [3H]-thymidine incorporation, and changes in proliferating cell nuclear antigen (PCNA). Although acrylamide (0.1 and 1 mM for 7, 11, 15, or 20 days) did not significantly (P > 0.05) affect [3H]-leucine or [3H]-thymidine incorporation, it significantly (P < 0.05) increased PCNA protein expression in astrocytes exposed to acrylamide for 15 and 20 days. Additional studies revealed that this effect on PCNA protein expression was not associated with activation of dopamine-2 (D2) receptors, given that quinpirole (10 microM added to cultures for the last hour of 7, 11, 15, or 20 days in culture), a selective D2 receptor agonist, did not produce results analogous to those seen with acrylamide treatment. Cotreatment of astrocytes with acrylamide (7, 11, 15, or 20 days) and the D2 receptor antagonist, sulpiride (1 microM for the last 6 h of exposure), also failed to reverse acrylamide's effect on PCNA protein induction. Taken together, these studies suggest that acrylamide promotes astrocytic cell proliferation in the CNS even though DNA synthesis did not appear stimulated.
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Affiliation(s)
- Michael Aschner
- Department of Pediatrics and Pharmacology, B-3307 Medical Center North, Vanderbilt University Medical Center, 1162 21st Avenue South, Nashville, Tennessee 37232-2495, USA.
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Fennell TR, Sumner SCJ, Snyder RW, Burgess J, Spicer R, Bridson WE, Friedman MA. Metabolism and Hemoglobin Adduct Formation of Acrylamide in Humans. Toxicol Sci 2004; 85:447-59. [PMID: 15625188 DOI: 10.1093/toxsci/kfi069] [Citation(s) in RCA: 168] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Acrylamide (AM), used in the manufacture of polyacrylamide and grouting agents, is produced during the cooking of foods. Workplace exposure to AM can occur through the dermal and inhalation routes. The objectives of this study were to evaluate the metabolism of AM in humans following oral administration, to compare hemoglobin adduct formation on oral and dermal administration, and to measure hormone levels. The health of the people exposed under controlled conditions was continually monitored. Prior to conducting exposures in humans, a low-dose study was conducted in rats administered 3 mg/kg (1,2,3-13C3) AM by gavage. The study protocol was reviewed and approved by Institute Review Boards both at RTI, which performed the sample analysis, and the clinical research center conducting the study. (1,2,3-13C3) AM was administered in an aqueous solution orally (single dose of 0.5, 1.0, or 3.0 mg/kg) or dermally (three daily doses of 3.0 mg/kg) to sterile male volunteers. Urine samples (3 mg/kg oral dose) were analyzed for AM metabolites using 13C NMR spectroscopy. Approximately 86% of the urinary metabolites were derived from GSH conjugation and excreted as N-acetyl-S-(3-amino-3-oxopropyl)cysteine and its S-oxide. Glycidamide, glyceramide, and low levels of N-acetyl-S-(3-amino-2-hydroxy-3-oxopropyl)cysteine were detected in urine. On oral administration, a linear dose response was observed for N-(2-carbamoylethyl)valine (AAVal) and N-(2-carbamoyl-2-hydroxyethyl)valine (GAVal) in hemoglobin. Dermal administration resulted in lower levels of AAVal and GAVal. This study indicated that humans metabolize AM via glycidamide to a lesser extent than rodents, and dermal uptake was approximately 6.6% of that observed with oral uptake.
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Affiliation(s)
- Timothy R Fennell
- Research Triangle Institute, Research Triangle Park, North Carolina 27709, USA.
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8
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Abstract
Acrylamide (ACM) has recently been found in fried and baked foods, suggesting widespread public exposure. ACM is an industrial chemical that causes neurotoxicity in humans and an increase in benign tumors of the endocrine system of laboratory rats. The U.S. EPA and the International Agency for Research on Cancer (IARC) have designated ACM as a probable human carcinogen based on the bioassay data and evidence for a DNA reactive mechanism. We report here an assessment of the published epidemiological data with regard to exposure to ACM. The results of an epidemiology mortality study of heavily exposed workers published in 1999 failed to reveal any increase in total cancer in this workforce. The average total exposure in the exposed group was equivalent to over 100% of the estimated average lifetime dietary intake, assuming a U.S. diet. However, this epidemiologic information had limited power to detect modest increases in specific tumors of the type reported in the rodent studies. Although the mortality study could not have picked up the small increases in cancer or in specific cancer types predicted by EPA's linear extrapolation model, research on biochemical and physiological mechanisms suggests that EPA's assessment overstates the potency, and therefore, the risk from foods and other sources of exposure may be lower than previously anticipated.
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Abstract
We assessed biochemical endpoints indicative of acute toxicity in neonatal rat primary astrocyte cultures exposed to acrylamide. Metallothionein (MT), glutamine synthetase (GS), glutamate/aspartate transporter (GLAST), and taurine transporter (tau-T) mRNA expression levels as well as cell volume were determined in astrocytes acutely treated with 0.1 and 1.0 mM acrylamide. Statistically significant changes in acrylamide treated astrocytes were noted for GS (0.1 mM) and GLAST (1.0 mM) mRNA expression levels. All other measurements were insignificant in comparison with controls, suggesting that astrocytic function is minimally compromised even at exceedingly high levels of acute acrylamide exposure.
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Affiliation(s)
- Michael Aschner
- Department of Physiology and Pharmacology and Interdisciplinary Program in Neuroscience, Wake Forest University School of Medicine, Winston-Salem, North Carolina 27157, USA.
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Abstract
Acrylamide monomer causes peripheral neurotoxicity, mutagenicity, clastogenicity, male reproductive toxicity, prenatal lethality, and endocrine-related tumors in rodents. Acrylamide (and/or its metabolite glycidamide) binds to dopamine receptors and spermatid protamines and inhibits activity of kinesin and dyneine, resulting in interference with neuronal intracellular transport and sperm motility. Glycidamide binds to various proteins and DNA. Acrylamide at low doses decreases litter size, with rats more sensitive than mice. At higher doses, sperm morphology and motility and neurotoxicity are affected, which decreases mating frequency. Acrylamide does not affect female reproduction (females exhibit neurotoxicity). Dominant lethal mutations cause decreased newborn litter size. The mechanisms of action appear to be: (1) acrylamide/glycidamide binding to spermatid protamines, causing dominant lethality and effects on sperm morphology; and (2) acrylamide binding to motor proteins, causing distal axonopathy, including hindlimb weakness/paresis, and effects on mounting, sperm motility, and intromission. Glycidamide-induced mutations appear to play no role in reproductive or neurologic toxicity.
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Affiliation(s)
- Rochelle W Tyl
- RTI, Center for Life Sciences and Toxicology, PO Box 12194, 3040 Cornwallis Road, Research Triangle Park, NC 27709-2194, USA.
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11
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Abstract
The cellular and molecular site and mode of action of acrylamide (ACR) leading to neurotoxicity has been investigated for four decades, without resolution. Although fast axonal transport compromise has been the central theme for several hypotheses, the results of many studies appear contradictory. Our analysis of the literature suggests that differing experimental designs and parameters of measurement are responsible for these discrepancies. Further investigation has demonstrated consistent inhibition of the quantity of bi-directional fast transport following single ACR exposures. Repeated compromise in fast anterograde transport occurs with each exposure. Modification of neurofilaments, microtubules, energy-generating metabolic enzymes and motor proteins are evaluated as potential sites of action causing the changes in fast transport. Supportive and contradictory data to the hypothesis that deficient delivery of fast-transported proteins to the axon causes, or contributes to, neurotoxicity are critically summarized. A hypothesis of ACR action is presented as a framework for future investigations.
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Affiliation(s)
- Dale W Sickles
- Department of Cellular Biology and Anatomy, Medical College of Georgia, Augusta 30912-2000, USA.
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Abstract
Acrylonitrile, a high volume organic chemical, was tested for reproductive effects in a three generation drinking water study with two matings per generation. Sprague-Dawley rats were exposed to acrylonitrile in drinking water at 0, 100, or 500 ppm. This corresponds to 0, 11+/-5 and 37+/-10 mg/kg, respectively, for males and 0, 20+/-3 and 40+/-8 mg/kg per day for the females, respectively. Water consumption was reduced in F0 rats in the 100 and 500 ppm groups. At 500 ppm, acrylonitrile reduced body weight gain and food intake of the first generation parental rats (F0). These parameters were not investigated at subsequent generations. The pup survival (both viability and lactation indices) was reduced at the 500 ppm treatment level in both matings of all three generations. Fostering the 500 ppm pups onto untreated mothers following the second mating lessened mortality, suggesting a maternal effect consistent with decreased water consumption. There was no remarkable change in the reproductive capacity in any of matings in rats at the 100 ppm concentration. In contrast, in all three generations, the body weights of the pups of the 500 ppm treatment level were reduced on Day 21 at both matings. No adverse findings were observed in the tissues of a limited number of third generation weanlings (F3b) upon gross and microscopic evaluation. No effect on the sciatic nerve was evident among the adult female rats held for 20 weeks after weaning of the second litter. There was a dose-related effect of acrylonitrile on gross masses in female rats at each parental generation held 20 weeks after the weaning of the second litter. Histopathological evaluation of these dams showed an increase in astrocytomas and zymbal gland tumors.
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Affiliation(s)
- M A Friedman
- Department of Pharmacology and Physiology, University of Medicine and Dentistry of New Jersey, Newark, USA.
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13
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Abstract
Acrylamide is a monomer of polyacrylamide, whose products are used in biochemistry, the manufacture of paper, water treatment, and as a soil stabilizer. While polymeric acrylamide is nontoxic, the monomer can cause several toxic effects and has the potential for human occupational exposure. While acrylamide is not mutagenic in prokaryotic mutagenesis assays, chronic acrylamide treatment in rodents has been shown to produce tumors in both rats and mice. The mechanism for the induction of tumors by acrylamide is not known. In the present study, we examined the possibility that acrylamide might induce cellular transformation, using Syrian hamster embryo (SHE) cell morphological transformation as well as potential mechanisms for the cellular transformation. Results showed that treatment with 0.5 mM and higher concentrations of acrylamide continuously for 7 days induced morphological transformation. Cotreatment with acrylamide and N-acetyl-L-cysteine (NAC), a sulfhydryl group donor, resulted in the reduction of acrylamide-induced morphological transformation in SHE cells. Cotreatment with 1-aminobenzotriazole (ABT), a nonspecific P450 inhibitor, and acrylamide produced no change in morphological transformation when compared to acrylamide treatment only. Cotreatment with acrylamide and DL-buthionone-[S,R]-sulfoximine (BSO), a selective inhibitor of gamma-glutamylcysteine synthetase, increased the percent of morphologically transformed colonies compared to acrylamide treatment alone. Acrylamide reduced GSH levels in SHE cells, and cotreatment with acrylamide and NAC prevented the acrylamide-induced reduction of GSH. BSO treatment with acrylamide enhanced the depletion of GSH. These results suggest that acrylamide itself, but not oxidative P450 metabolites of acrylamide appear to be involved in acrylamide-induced cellular transformation and that cellular thiol status (possibly GSH) is involved in acrylamide-induced morphological transformation.
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Affiliation(s)
- Joungjoa Park
- Division of Toxicology, Department of Pharmacology and Toxicology, Indiana University School of Medicine, 635 Barnhill Dr., MS 1021, Indianapolis, Indiana 46202, USA
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Abstract
Changes in the tibiotalar contact characteristics were investigated using eight fresh frozen cadaver ankle specimens to further develop an established model of the acquired flatfoot deformity. The deformity was simulated by sectioning the tendons and ligaments of the ankle and foot that normally support the longitudinal arch. Axial loads of 1,350 N were applied to the foot in a neutral position in both the intact specimen and flatfoot model. The flatfoot condition resulted in significant lateral shifts of 5.28 mm in global contact area and 11.26 mm in the location of peak pressure, and in a small but significant posterior shift of 1.14 mm in global contact area. The flatfoot condition also resulted in a significant, 35%, reduction in contact area. Significant increases in mean pressure, 14%, and peak pressure, 13%, were also found, but were not in proportion to the relatively large decrease in contact area. This suggests a transfer of load off of the talar dome. Increased loading of the lateral facet and fibula are suspected. The lateral shift in the contact region created a local increase in mean contact pressure that may be responsible for long term degenerative changes in patients with this deformity.
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Affiliation(s)
- M A Friedman
- The University of Chicago Medical Center, Department of Surgery, Section of Orthopaedic and Rehabilitation Medicine, Illinois 60637, USA
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Tyla RW, Friedman MA, Losco PE, Fisher LC, Johnson KA, Strother DE, Wolf CH. Rat two-generation reproduction and dominant lethal study of acrylamide in drinking water. Reprod Toxicol 2000; 14:385-401. [PMID: 11020651 DOI: 10.1016/s0890-6238(00)00097-6] [Citation(s) in RCA: 67] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Fischer 344 (F344) F(0) weanling rats, 30/sex/group, were exposed to acrylamide in drinking water at 0.0, 0.5, 2.0, or 5.0 mg/kg/day for 10 weeks and then mated. Exposure of F(0) females continued through gestation and lactation of F(1) litters. F(0) males, after F(0) mating, were removed from exposure and mated (one male: two untreated females) for the dominant lethal (DL) assay. Thirty F(l) weanlings/sex/group were exposed for 11 weeks to the same dose levels as their parents, and then mated to produce F(2) offspring. F(0) and F(l) parents and F(1) and F(2) weanlings were necropsied. Prebreeding exposure of F(0) and F(l) animals resulted in systemic toxicity at 2.0 to 5.0 mg/kg/day, with head tilt and/or foot splay increased at 0.5 to 5.0 mg/kg/day. F(0) and F(l) reproductive indices and gestational length were unaffected. Implantations and live pups/litter at birth were reduced at 5.0 mg/kg/day. Survival of F(l) and F(2) pups was reduced at 5.0 mg/kg/day for PND 0 through 4 only. In the DL assay, total and live implants were reduced, pre- and postimplantation loss was increased, and the frequency of DL factors (F(L)%) was increased at 5.0 mg/kg/day. At 5.0 mg/kg/day, adult F(l) male peripheral nerves exhibited axonal fragmentation and/or swelling; F(l) female spinal cord sections were unremarkable. The NOEL for prenatal DL was 2.0 mg/kg/day; the NOEL for adult systemic toxicity, including neurotoxicity, was < or = 0.5 mg/kg/day. Therefore, neurotoxicity and DL were differentially affected.
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Affiliation(s)
- R W Tyla
- Bushy Run Research Center/Union Carbide Corp., Export, PA, USA.
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Wilfley DE, Friedman MA, Dounchis JZ, Stein RI, Welch RR, Ball SA. Comorbid psychopathology in binge eating disorder: relation to eating disorder severity at baseline and following treatment. J Consult Clin Psychol 2000; 68:641-9. [PMID: 10965639] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2023]
Abstract
Individuals with binge eating disorder (BED) have high rates of comorbid psychopathology, yet little is known about the relation of comorbidity to eating disorder features or response to treatment. These issues were examined among 162 BED patients participating in a psychotherapy trial. Axis I psychopathology was not significantly related to baseline eating disorder severity, as measured by the Structured Clinical Interview for DSM-III-R (SCID-I and SCID-II) and the Eating Disorder Examination. However, presence of Axis II psychopathology was significantly related to more severe binge eating and eating disorder psychopathology at baseline. Although overall presence of Axis II psychopathology did not predict treatment outcome, presence of Cluster B personality disorders predicted significantly higher levels of binge eating at 1 year following treatment. Results suggest the need to consider Cluster B disorders when designing treatments for BED.
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Affiliation(s)
- D E Wilfley
- Joint Doctoral Program in Clinical Psychology, San Diego State University, USA.
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Abstract
To determine whether there is a relationship between the reproductive and neurotoxic effects of acrylamide monomer (AM), the first week of the study design of Sublet et al. ¿14 was duplicated: Long-Evans male rats were gavaged with AM in water, 25/group, at 0, 5, 15, 30, 45, or 60 mg/kg/day for 5 days (days 1 through 5). On Day 8, males were paired overnight with untreated virgin females (1 : 1) in proestrus/estrus. On day 9, males were evaluated for forelimb and hindlimb grip strength. Five males/group were perfusion fixed, 20/group were used for andrologic assessment, and all were necropsied. Perfusion-fixed sciatic nerves were examined histologically. Sperm-positive females were examined for preimplantation and postimplantation loss at midpregnancy. At 15 to 60 mg/kg/day, males exhibited significantly reduced weight gain, reduced mating, fertility, and pregnancy indices by trend analysis (significant at 60 mg/kg/d by pairwise comparison), and increased postimplantation loss and dominant lethal factor, F(L)%, at 45 and 60 mg/kg/day. At 60 mg/kg/day, the sperm beat cross frequency was increased, with no significant effects on epididymal sperm motility or concentration, and hindlimb grip strength was decreased, with no pathologic lesions in sciatic nerves. Therefore, epididymal sperm, mating, and neurotoxic effects were observed at AM doses that also resulted in increased postimplantation loss, possibly by different mechanisms.
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Affiliation(s)
- R W Tyl
- Research Triangle Institute, PO Box 12194, Research Triangle Park, NC 27709-2194, USA.
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Adler ID, Baumgartner A, Gonda H, Friedman MA, Skerhut M. 1-Aminobenzotriazole inhibits acrylamide-induced dominant lethal effects in spermatids of male mice. Mutagenesis 2000; 15:133-6. [PMID: 10719038 DOI: 10.1093/mutage/15.2.133] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Acrylamide (AA) is a germ cell mutagen and induces clastogenic effects predominantly in spermatids of mice. The mechanism of AA clastogenicity has been a matter of dispute. Since the reactivity of AA with DNA is low but is high with proteins containing SH groups, it was suggested that protamine alkylation could be the mechansim of clastogenicity by AA in spermatids. This was substantiated by the observation that the time course of protamine alkylation and dominant lethal effects in spermatids of mice induced by AA was strictly parallel. Another suggestion was that AA may be metabolized by cytochrome P-450 to the epoxide glycidamide (GA), which is then the ultimate DNA-reactive clastogen. This suggestion was based on the similarity of the stage specificity pattern for dominant lethality and heritable translocation induction by AA and GA. To test this latter assumption, 1-aminobenzotriazole (ABT), an inhibitor of P-450 metabolism, was used in the present experiments. Male mice were pretreated with ABT (3x50 mg/kg) on three consecutive days followed by AA treatment (125 mg/kg) on day 4. Parallel groups of animals were treated with AA (125 mg/kg), ABT (3x50 mg/kg) or with the solvent double-distilled water. The experiment was repeated once with slightly varied mating parameters. The results of both experiments showed that ABT inhibited or significantly reduced the AA-induced dominant lethal effects. Thus, the present data support the hypothesis that the AA metabolite GA is the ultimate clastogen in mouse spermatids.
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Affiliation(s)
- I D Adler
- GSF-Institute of Mammalian Genetics, Ingolstaedter Landstrabetae 1, D-85764, Neuherberg, Germany.
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Abstract
Using the rat pheochromocytoma cell line (PC12), we present molecular evidence that the neurotoxicant acrylamide directly induces neurofilament gene expression, and the signaling pathways are initially distinctive from, but eventually merged into, that for nerve growth factor (NGF)-induced neurofilament expression. In PC12 cells, acrylamide increased neurofilament protein levels and synthesis. Acrylamide had no effect on the stability of neurofilament mRNAs suggesting that it directly increased neurofilament mRNA synthesis. K252a, a selective inhibitor for NGF receptor gp140trk, had no effect on acrylamide induction, but completely inhibited NGF-induced neurofilament protein synthesis. Therefore, the initial step for acrylamide signaling was distinctive from NGF. Dexamethasone reversed the effects of both NGF and acrylamide on neurofilament protein levels and synthesis indicated that there is a dexamethasone-sensitive signaling step upon which NGF and acrylamide merge, suggesting involvement of transcription-activating proteins like AP-1. These results, taken together with previous studies of transgenic mice that overexpress neurofilament genes, may partially explain the mechanisms of neurofilament accumulation in distal parts of large axons, a pathognomonic feature of acrylamide neurotoxicity in animals.
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Affiliation(s)
- W W Lin
- Department of Pharmacology, Duke University Medical Center, Durham, NC 27710, USA
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22
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Abstract
Modulation of endocrine function is frequently a confounding factor in the interpretation of chronic rodent toxicology studies. Of particular interest are agents that cause deviation of thyroid hormone homeostasis and result in thyroid cancer for rodents. An endocrine challenge test (ECT), commonly used to study endocrine organ health in human and veterinary medicine, quantifies the response of the thyroid to tropic hormones. This study compared the response of Fischer (F344) and Sprague-Dawley (SD) rats to a thyrotropin-releasing hormone (TRH) ECT and a thyroid-stimulating hormone (TSH) ECT and characterized the dose-response curve. TSH, thyroxine (T4), triiodothyronine (T3), and prolactin responses were characterized for several doses of TRH over a 4-h time period. Animals were equipped with intra-atrial cannulae and were free moving at all times during blood sampling. Both strains of rats responded to intravenous TRH by releasing TSH into their blood in a dose-responsive fashion. At doses of > or = 100 ng, TSH concentrations were increased by more than 2-fold at 2 min. Concentrations reached a maximum at 15 min for doses of 100 ng/100 g body weight (bw) to 5000 ng/100g bw. The effective dose 50 (ED50) of TRH (that dose causing release of half maximal TSH concentrations) was 61 ng in F344 rats and 78 ng in SD rats. The ED75 was 173 ng and 217 ng/100 g bw, respectively. The response of T4 and T3 after TRH ECT and TSH ECT was highly variable. F344 rats responded with an increase in levels of both hormones, starting at 60 min and continuing through 240 min. In SD rats, the presence of a thyroid hormone response (T4) was present, although that of T3 was not clear. These data provide essential information for design of toxicology studies focused on the effects of toxicants and drugs on the pituitary-thyroid axis.
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Affiliation(s)
- P A Fail
- Research Triangle Institute, Research Triangle Park, North Carolina 27709-2194, USA.
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Abstract
We duplicated the study design of Husain et al. (Ind Health 1987; 25:19-28) to determine whether maternal exposure to acrylamide monomer (AM) resulted in offspring neurotoxicity. Wistar rat dams with litters (15/group) were gavaged with AM in saline at 0 or 25.0 mg/kg/d throughout lactation (pnd 0-21). Maternal feed and water consumption, body weights (BW), and Functional Observational Battery (FOB) were recorded. At weaning (pnd 21), maternal sciatic nerves were examined histologically. Male offspring were retained until pnd 91, with BW and grip strength evaluations. Dosed dams exhibited progressive toxicity, including mortality (two), severely reduced feed and water consumption, BW, and BW gain, and behavioral neurotoxicity (with no sciatic nerve pathology). Nursing offspring at 25.0 mg/kg/d exhibited increased mortality and reduced BW associated with little/no milk in stomachs. Postwean males at 25.0 mg/kg/d exhibited normal BW gain and increasing grip strength over time. Therefore, AM caused maternal toxicity; offspring effects during lactation were consistent with inanition from maternal toxicity. Postwean males exhibited recovery with no signs of AM-mediated toxicity. These results do not support the conclusions of Husain et al.
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Affiliation(s)
- M A Friedman
- University of Medicine and Dentistry of New Jersey, Newark 07103-2757, USA
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24
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Abstract
OBJECTIVE This study examined whether married individuals have comparable body image disturbance to nonmarried individuals and whether the quality of a marital relationship is significantly related to body image disturbance in a sample of dieters. METHOD Measures of marital status, marital satisfaction, and body dissatisfaction were administered to a sample of 16,377 subjects who had tried to lose weight at least once within the previous 3 years. RESULTS Marital status was not associated with increased body dissatisfaction. Marital satisfaction was significantly related to body dissatisfaction when controlling for age, body mass index, self-esteem, and gender. DISCUSSION Body dissatisfaction occurs at comparable levels among married and single individuals and the study of marital functioning among eating-disordered individuals represents a large gap in the literature.
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Affiliation(s)
- M A Friedman
- Department of Psychology, Yale University, New Haven, Connecticut 06520-8205, USA
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25
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Abstract
This article outlines some of the complexities and challenges confronting researchers and the US Food and Drug Administration (FDA) in the area of evaluation of antimetastatic and other novel anticancer therapies. The scientific regulatory matrix utilized by the FDA is outlined. Subsequently, the complications encountered when designing and interpreting studies of antimetastatic drugs are described, and finally changes in the regulatory landscape both within the USA and internationally are considered.
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Affiliation(s)
- M A Friedman
- US Food and Drug Administration, Rockville, MD 20857, USA
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26
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Abstract
The removal of 5 pharmaceuticals from the market in a 12-month period because of unexpected adverse events raised concerns about the adequacy of the drug review process at the US Food and Drug Administration (FDA). Specifically, concerns were raised about improvements in drug review efficiency that significantly reduced FDA review times. We have reviewed the circumstances of the 5 removals to determine whether there was any relationship to the increased efficiencies in the drug review process. When the removed drugs were analyzed by date of approval, no increase in the number of drugs taken off the market was seen, demonstrating that reduced review processing time was not the reason for the cluster of removals. We conclude that the agency's drug review procedures and postmarketing surveillance system after a drug has been marketed are currently adequate but must continually adjust to future challenges.
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Affiliation(s)
- M A Friedman
- Office of the Commissioner, The US Food and Drug Administration, Rockville, MD 20857, USA
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Kadry AM, Friedman MA, Abdel-Rahman MS. Pharmacokinetics of acrylamide after oral administration in male rats. Environ Toxicol Pharmacol 1999; 7:127-133. [PMID: 21781917 DOI: 10.1016/s1382-6689(99)00005-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/1998] [Revised: 01/06/1999] [Accepted: 01/07/1999] [Indexed: 05/31/2023]
Abstract
Acrylamide (AMD) is a commonly used industrial chemical. However, it produces a dying back type of peripheral neuropathy in animals and man. This study was performed to investigate the pharmacokinetics of AMD after oral administration at 50 mg/g ([1-(14)C]AMD) in male Sprague-Dawley rats. Absorption from the gastrointestinal tract was rapid and radioactivity was detected in blood 5 min post-administration. The peak plasma concentration occurred 38 min after administration and was equivalent to 47 μg/ml. The elimination pattern for plasma was fitted to a one-compartment model with 6 h half-life. However, in the blood the elimination pattern was fitted to a two-compartment model with 7.93 and 374 h for distribution and elimination phases, respectively. Tissue concentrations of radioactivity determined at 28 and 144 h post-administration differed substantially. After 28 h the highest activity was in the gastric content, followed by stomach, lung, bone marrow and skin, while after 144 h the order of total radioactivity was lung>bone marrow>esophagus. The activities in the rest of the organs in both experiments were very low. The excretion study revealed that the kidney is the major route of elimination and the majority of radioactivity in urine was excreted during the first 12 h. The feces contained approximately 10% of the administered dose after 144 h. This study indicated that AMD is rapidly absorbed from the rat's gastrointestinal tract, distributed and eliminated from the body. AMD bound but did not accumulate in the erythrocytes or the neural tissues.
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Affiliation(s)
- A M Kadry
- Pharmacology and Physiology Department, University of Medicine and Dentistry of New Jersey, New Jersey Medical School, 185 South Orange Avenue, Newark, NJ 07103-2714, USA
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28
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Abstract
High exposure to the acrylamide monomer has been associated with neuropathy and neurotoxic effects. Chronic lower exposure causes endocrine disruption associated with thyroid, testicular, and mammary tumors. To investigate mechanisms of endocrine disruption, short-term, low-level oral dosing studies were conducted. Weanling female Fischer 344 rats were acclimatized for two weeks before dosing. Controls were given distilled water by gavage and rats in other groups were given acrylamide at doses of 2 mg/kg/day and 15 mg/kg/day for 2 or 7 days by gavage. Twenty-four h after the last dose, the rats were killed by decapitation. Trunk blood was collected for hormone analyses and tissues for histopathological examination. There were no toxicity-related deaths, no clinical signs of toxicity, and no significant difference in the mean body weight of animal groups. Histopathological examination of select tissues showed no lesions of pathologic significance. Plasma thyroxine (T4), thyroid stimulating hormone (TSH), prolactin (PRL), and pituitary TSH and PRL analyses did not reveal significant changes between control vs. treated rats. In the 7-day study, however, there was a slight dose-dependent increase in plasma T4 and a slight dose-dependent decrease in plasma TSH. Thyroid gland morphometry showed a significant (p < 0.05) decrease in the colloid area and a significant increase (p < 0.05) in the follicular cell height of treated rats as compared to controls. The follicular area shrinkage was similar in both studies. These results show a very early endocrine response to very low levels of toxic insult and opens other venues to further investigate the mechanisms of endocrine disruption by acrylamide.
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Affiliation(s)
- M A Khan
- Department of Veterinary Biosciences, College of Veterinary Medicine, University of Illinois at Urbana-Champaign 61802, USA
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29
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Abstract
The auditory and electrosensory systems contain circuits that are specialized for the encoding and processing of microsecond time differences. Analysis of these circuits in two specialists, weakly electric fish and barn owls, has uncovered common design principles and illuminated some aspects of their evolution.
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Affiliation(s)
- C E Carr
- Department of Zoology, University of Maryland, College Park, MD 20742, USA.
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30
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Friedman MA, Schwartz MB, Brownell KD. Differential relation of psychological functioning with the history and experience of weight cycling. J Consult Clin Psychol 1998. [PMID: 9735581 DOI: 10.1037//0022-006x.66.4.646] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Two measures of weight cycling and indexes of psychological functioning were examined in a large sample of dieters. History of weight cycling was assessed to include number of dieting attempts, total lifetime weight lost and regained, and number of weight cycles over 20 lb (9.1 kg). Experience of weight cycling measured perception of being a yo-yo dieter and perceived success at maintaining past weight losses. Experience was more strongly related than history to all psychological measures. Further, when controlling for the effects of age, body mass index, and experience, the relation between history and the psychological variables was nonsignificant. This finding suggests that an individual's perception of being a weight cycler may be more related to psychological problems than the actual number of pounds lost and regained over time.
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Affiliation(s)
- M A Friedman
- Department of Psychology, Yale University, New Haven, Connecticut 06520-8205, USA
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31
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Damjanov I, Friedman MA. Mesotheliomas of tunica vaginalis testis of Fischer 344 (F344) rats treated with acrylamide: a light and electron microscopy study. In Vivo 1998; 12:495-502. [PMID: 9827357] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
The incidence of spontaneous mesotheliomas of the tunica vaginalis testis, documented to be 1.3% in Fischer 344 rats can be increased by long term exposure to acrylamide. The light microscopic and electron microscopic features of tumors developing spontaneously in control animals were compared with those that developed in acrylamide treated animals to determine whether the tumors in the experimental group have any distinctive characteristics. The experimental group comprised three subgroups, i.e. animals exposed to acrylamide in three doses 0.1, 0.5 or 2.0 mg/kg/day over a period of 104 weeks. A total of 35 tumors were examined--7 in control group, 9 in low-dose group, 8 in mid-dose group and 11 in the high-dose group. Most tumors measured less than 1 cm in diameter in aggregate and approximately one-third of all tumors were of microscopic size, less than 5 mm in diameter. All tumors were classified as epithelial mesotheliomas. Three distinct microscopic patterns were recognized (papillary, tubular or solid). All tumors had papillary features, and focally showed some tubular or solid components. No ultrastructural differences were found between tumors of the four groups of animals. It was concluded that the tumors that developed in the tunica vaginalis testis of acrylamide treated animals do not differ morphologically from those that developed spontaneously in control animals. Cellular uniformity, small size of lesions and the absence of perotoneal seeding and metastasis suggests that the mesotheliomas of tunica vaginalis testis of Fischer 344 rats in this study were benign and equivalent to human benign mesothelioma of tunica vaginalis testis or adenomatoid tumors.
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Affiliation(s)
- I Damjanov
- Department of Pathology, University of Kansas, School of Medicine, Kansas City, USA
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Friedman MA, Schwartz MB, Brownell KD. Differential relation of psychological functioning with the history and experience of weight cycling. J Consult Clin Psychol 1998; 66:646-50. [PMID: 9735581 DOI: 10.1037/0022-006x.66.4.646] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Two measures of weight cycling and indexes of psychological functioning were examined in a large sample of dieters. History of weight cycling was assessed to include number of dieting attempts, total lifetime weight lost and regained, and number of weight cycles over 20 lb (9.1 kg). Experience of weight cycling measured perception of being a yo-yo dieter and perceived success at maintaining past weight losses. Experience was more strongly related than history to all psychological measures. Further, when controlling for the effects of age, body mass index, and experience, the relation between history and the psychological variables was nonsignificant. This finding suggests that an individual's perception of being a weight cycler may be more related to psychological problems than the actual number of pounds lost and regained over time.
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Affiliation(s)
- M A Friedman
- Department of Psychology, Yale University, New Haven, Connecticut 06520-8205, USA
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Abstract
OBJECTIVE The cognitive-behavioral model of bulimia nervosa suggests that maladaptive cognitions are associated with the development and maintenance of bulimia nervosa. This study was conducted to evaluate (a) the relation between bulimic symptomatology and the cognitive-personality styles of sociotropy (reflecting themes of acceptance and approval) and autonomy (reflecting themes of independence and achievement), and (b) the specificity of the relation between these two cognitive-personality styles and bulimic versus depressive symptoms. METHOD 105 undergraduate women were administered self-report measures of sociotropy and autonomy, as well as bulimic and depressive symptomatology. RESULTS Whereas both sociotropy and autonomy were related to bulimic symptomatology, only sociotropy was uniquely associated with symptoms of bulimia when controlling for the effects of depressive symptoms. DISCUSSION Themes of acceptance and approval may be important cognitive-personality features of bulimia nervosa.
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Affiliation(s)
- M A Friedman
- Department of Psychology, Yale University, New Haven, Connecticut 06520-8205, USA
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Friedman MA, Hopkins CD. Neural substrates for species recognition in the time-coding electrosensory pathway of mormyrid electric fish. J Neurosci 1998; 18:1171-85. [PMID: 9437037 PMCID: PMC6792764] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/1997] [Revised: 11/07/1997] [Accepted: 11/17/1997] [Indexed: 02/05/2023] Open
Abstract
Mormyrid electric fish have species- and sex-typical electric organ discharges (EODs). One class of tuberous electroreceptors, the knollenorgans, plays a critical role in electric communication; one function is species recognition of EOD waveforms. In this paper, we describe cell types in the knollenorgan central pathway, which appear responsible for analysis of the temporal patterns of spikes encoded by the knollenorgans in response to EOD stimuli. Secondary sensory neurons in the nucleus of the electrosensory lateral line lobe (NELL) act as relays of peripheral responses. They fire a single phase-locked spike to an outside positive-going voltage step. Axons from the NELL project to the toral nucleus exterolateralis pars anterior (ELa). Immediately after they enter the ELa, they send collaterals to terminate on one to three ELa large cells and then continue in a lengthy neuronal pathway that traverses the ELa several times. After a path length of up to 5 mm, the NELL axon terminates on as many as 70 ELa small cells. Thus the large cells appear to be excited first, followed by the small cells, with the intervening length of the axon serving as a delay line. The large cells also respond with phase-locked spikes to voltage steps. Large cell axons extend for approximately 1 mm and terminate on several small cells within the ELa. The terminals are known to be GABAergic inputs and are presumed inhibitory. We propose that small cells receive direct inhibition from large cells and delayed excitation from NELL axons. The small cells may act as anti-co-incidence detectors to analyze the temporal structure of the EOD waveform.
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Affiliation(s)
- M A Friedman
- Section of Neurobiology and Behavior, Cornell University, Ithaca, New York 14853, USA
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35
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Amagai S, Friedman MA, Hopkins CD. Time coding in the midbrain of mormyrid electric fish. I. Physiology and anatomy of cells in the nucleus exterolateralis pars anterior. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 1998; 182:115-30. [PMID: 9463915 DOI: 10.1007/s003590050163] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
In mormyrid electric fish, species-specific electric organ discharge waveforms are thought to be analyzed by the Knollenorgan electroreceptor subsystem. The midbrain anterior and posterior exterolateral nuclei (ELa and ELp) are thought to be the sites of this analysis. This paper is an electrophysiological study of the properties of the neurons in ELa. We recorded intracellularly from three classes of cells within ELa: the afferent axons from the nucleus of the electrosensory lateral line lobe (NELL), the large interstitial cells of ELa and an unidentified cell type. The large cells and the NELL axons were identified by intracellular injection of biocytin and are physiologically similar. Cells in ELa responded to square pulse stimuli with one or more time-locked action potentials with 2.8-3.0 ms latency. Both large cells and NELL axons arborized extensively in ELa and contacted numerous small cells. Based on the pattern of arborizations, we constructed a counter-current flow model of temporal coding by the small cells of ELa. We postulate that individual small cells are not selectively tuned for specific stimulus durations, but rather, the firing patterns of groups of small cells must be analyzed by neurons further up in the sensory hierarchy to determine the stimulus duration.
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Affiliation(s)
- S Amagai
- Section of Neurobiology and Behavior, Cornell University, Ithaca, NY 14853-2702, USA.
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Friedman MA. Remarks of the Lead Deputy Commissioner of the Food and Drug Administration. Food Drug Law J 1998; 53:19-23. [PMID: 11795333] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Affiliation(s)
- M A Friedman
- Food and Drug Administration, Rockville, MD, USA
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37
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Friedman MA, Kawasaki M. Calretinin-like immunoreactivity in mormyrid and gymnarchid electrosensory and electromotor systems. J Comp Neurol 1997; 387:341-57. [PMID: 9335419] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Calretinin-like immunoreactivity was examined in the electrosensory and electromotor systems of the two families of mormyriform electric fish. Mormyrid fish showed the strongest immunoreactivity in the knollenorgan electroreceptor pathway; in the nucleus of the electrosensory lateral line lobe (ELL) and the big cells of the nucleus exterolateralis pars anterior. Mormyromast and ampullary zones of the ELL showed calretinin-like immunoreactivity in the ganglion, granule, and intermediate cell and fiber layers. Mormyromast zones additionally showed labeling of apical dendrites and commissural cells, but the ampullary zone did not. In the electromotor system, two nuclei in the corollary discharge pathway showed labeling: in the paratrigeminal command-associated nucleus and the juxtalobar nucleus. Gymnarchus niloticus (Gymnarchidae) showed strongest calretinin-like immunoreactivity in part of the phase-coding pathway; in S-type electroreceptor afferents. Zones of the ELL not receiving phase-coder input had weak labeling. The electromotor system showed labeling in the lateral relay nucleus and less strongly in the medullary relay nucleus, but none in the pacemaker. The concentration of calcium-binding proteins in mormyrid and gymnarchid time-coding electrosensory pathways is consistent with the hypothesis that they play a role in preserving temporal information across synapses. Cell types that encode temporal characteristics of stimuli in precise spike times have high levels of calcium-binding proteins, but cells that re-code temporal information into presence or magnitude of activity have low levels. Some cell types in the electromotor pathways and early in the time-coding electrosensory pathways do not follow this hypothesis, and therefore preserve temporal information using a mechanism independent of calcium-binding proteins. In particular, electromotor systems may use extensive electrotonic coupling within nuclei to ensure precise timing.
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Affiliation(s)
- M A Friedman
- Section of Neurobiology and Behavior, Cornell University, Ithaca, New York 14853, USA.
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Abstract
The aim of this study was to examine whether overweight binge eaters demonstrate similar perceptions of family interactions and views of the self as do normal-weight bulimics. We compared 37 obese binge eaters and 37 normal-weight bulimics to 38 normal-weight non-bulimic controls, and 10 overweight nonbulimic controls on the Bulimia Test (BULIT). Profile of Mood States (POMS), Structural Analysis of Social Behavior (SASB) Short Form, which includes measure of hostility of family interactions and self-directed hostility; the Family Interaction Survey (FIS), and a measure of history of physical and sexual abuse and familial psychopathology. Both normal-weight bulimics and overweight binge eaters differed from nonbulimic controls across all measures of symptomatology, family functioning, history of abuse, familial psychopathology, and self-directed hostility. Normal-weight bulimics demonstrated significantly higher BULIT scores and self-directed hostility than did overweight binge eaters. Post hoc analysis showed that among binge eaters and bulimics, self-directed hostility accounted for a significant percentage of the variance of BULIT scores when controlling for the effects of age, BMI, family hostility, and mood. The possible role of self-directed hostility in the maintenance of bulimic symptomatology is discussed.
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Abstract
Acrylamide (ACR) is an environmental toxicant and prototypic tool for studying mechanisms of peripheral neuropathies. Reductions in fast anterograde axonal transport (faAXT) are thought to be a critical step leading to axonal degeneration. Kinesin and microtubules (MT) were evaluated as molecular sites of action using an in vitro MT motility assay. The number of locomoting MT which lifted from a bed of kinesin (MT detachments or MTD), increased from 7% in controls to 80, 89, and 100% following preincubation of kinesin (37 degrees C, 20 min) with 0.1, 0.5, or 1.0 mM ACR, respectively; rates were variably reduced by as much as 20%. Similar alterations were observed with N-ethylmaleimide. A non-neurotoxic analogue, propionamide (1mM), had no effect on either parameter. Preincubation of taxol-stabilized MT with ACR produced a dose-dependent increase in MTD but no changes in rate. We conclude that kinesin and MT are covalently modified by ACR resulting in reduced affinity for each other. The greater sensitivity of kinesin indicates that a primary cause of transient, ACR-induced reductions in faAXT is covalent modification of kinesin. Such reductions in faAXT may be sufficient to produce axonal degeneration. Further, ACR may prove useful as a pharmacological tool to decipher the complex mechanics of kinesin-MT interactions.
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Affiliation(s)
- D W Sickles
- Department of Cellular Biology and Anatomy, Medical College of Georgia, Augusta 30912-2000, USA
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Tejeda HA, Green SB, Trimble EL, Ford L, High JL, Ungerleider RS, Friedman MA, Brawley OW. Representation of African-Americans, Hispanics, and whites in National Cancer Institute cancer treatment trials. J Natl Cancer Inst 1996; 88:812-6. [PMID: 8637047 DOI: 10.1093/jnci/88.12.812] [Citation(s) in RCA: 204] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
BACKGROUND The National Cancer Institute (NCI)-sponsored clinical trials cooperative groups place more than 25 000 American patients in treatment trials every year. Equal access and proportional representation of all races/ethnicities is desired. PURPOSE Our objectives were to evaluate the inclusion of African-Americans, Hispanics, and non-Hispanic whites in NCI-sponsored treatment trials and to determine if there is proportional racial/ethnic representation. METHODS During the period of January 1, 1991, through June 30, 1994, 99 495 cancer patients were enrolled in clinical trials and declared themselves as non-Hispanic black, non-Hispanic white, or Hispanic (of any race). In the analysis, participants in NCI treatment trials were subdivided into three age groups: birth to 19 years, 20-49 years, and 50 or more years. The racial/ethnic composition of each of these age groups was compared with the racial/ethnic makeup of the American population with cancer. Estimates of the number of incident cancer cases per year were made for each racial/ethnic group within each age group using data from the Surveillance, Epidemiology, and End Results (SEER) Program and the 1990 Census. The percentage of all cancer patients who were in each racial/ethnic group were compared with the population that entered clinical trials. Comparisons are also made separately for patients with leukemia and breast, colorectal, lung, and prostate cancers. RESULTS Among patients 0-19 years old, 20-49 years old, and 50 years old or older there is relatively proportional representation of non-Hispanic blacks, Hispanics, and non-Hispanic whites in trials. It is noted that more than 70% of cancer patients aged 0-19 years are estimated to enter cooperative group clinical trials compared with 4.0% of cancer patients aged 20-49 years and 1.5% of patients aged 50 years or older. CONCLUSIONS Accrual of American cancer patients to NCI-sponsored treatment trials generally parallels the incident burden of disease among non-Hispanic African-Americans, Hispanics, and non-Hispanic whites. IMPLICATIONS This study shows that the NCI clinical trials are, as a whole, racially/ethnically representative of the American population and suggests that there is equal access to NCI clinical trials.
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Affiliation(s)
- H A Tejeda
- St. Peter's Medical Center (UMDNJ), Department of Medicine, New Brunswick, NJ 08903-0591, USA
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41
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Abstract
A previous study has shown that acrylonitrile (ACN) has a long half-life in rainbow trout muscle and that [14C]ACN appears to be bound to a 10,000-Da protein in muscle. The labeled protein was purified from muscle of trout exposed to [14C]ACN, separated on 20% SDS-PAGE, and digested for amino acid analysis and sequence analysis. These studies indicated that the labeled protein was the Ca(2+)-binding protein parvalbumin. Parvalbumin is an important calcium-binding protein thought to be involved in the regulation of calcium levels in various parts of the body ranging from neurons to fast-twitch muscle contractions. To study the reaction between parvalbumin and [14C]ACN, frog parvalbumin was incubated with [14C]ACN in vitro under various conditions. These studies indicated that the maximum labeling occurred at 1 nmol/nmol parvalbumin and at pH 7. Amino acid analysis of the labeled protein indicated that the labeled amino acid was probably histidine, and endoproteinase Glu-C (V-8) digestion studies revealed that the 14C was in the 1-81 amino acid segment of the protein, an area that contains two histidines.
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Affiliation(s)
- J J Lech
- Department of Pharmacology and Toxicology, Medical College of Wisconsin, Milwaukee 53226, USA
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42
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Abrams JS, Phillips PH, Friedman MA. Meeting highlights: a reappraisal of research results for the local treatment of early stage breast cancer. J Natl Cancer Inst 1995; 87:1837-45. [PMID: 7494227 DOI: 10.1093/jnci/87.24.1837] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Affiliation(s)
- J S Abrams
- Division of Cancer Treatment, National Cancer Institute, Bethesda, MD, USA
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43
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Abstract
A lifetime oncogenicity study in Fischer 344 rats was conducted to accurately characterize the carcinogenic potency of acrylamide. Acrylamide was administered in drinking water throughout the 106-week study at concentrations required to provide a dose of 0, 0.1, 0.5, or 2.0 mg/kg/day to males or 0, 1.0, or 3.0 mg/kg/day to females. Complete necropsy and gross pathology examinations were performed on all study animals. Histopathology examinations were conducted on selected tissues of all high-dose and control animals. Selected tissues from intermediate and low-dose groups were subjected to histopathological examinations as required to clarify high- and controldose group observations. There was no visual observation of neurotoxicity in any study animal but sciatic nerve degeneration was observed in the male and female high-dose groups. Increased mortality related to acrylamide was observed in the high- dose male group from Month 17 to the end of the study and in the high-dose females during Month 24. Mesotheliomas of the testicular tunic were significantly increased in the high-dose male group. The combined incidence of mammary gland adenocarcinomas and fibroadenomas was significantly increased in both acrylamide-dosed female groups. Males and females in the high-dose groups as well as females of the low-dose group had significantly (p<0.001) increased thyroid follicular cell adenomas and adenocarcinomas. A variety of other tumor types observed with increased incidence in a previous acrylamide onco genicity study (i.e., combined CNS glial neoplasms, papillomas of the oral cavity, adenomas of the clitoral gland, and uterine adenocarcinomas) were not observed to be present at increased incidence in this study. This study confirms previously described acrylamide induction of benign tumors of the thyroid and mammary glands as well as mesotheliomas of the testis. By using a larger number of animals with an unbalanced study design, this study showed that acrylamide did not induce glial tumors and demonstrated that the no-observable-effect level for scrotal mesotheliomas is 0.5 mg/kg. It also demonstrated that the in creased incidence of mammary tumors was again within historical control ranges.
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Affiliation(s)
- M A Friedman
- Cytec Industries Incorporated, West Paterson, New Jersey 07424, USA
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44
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Christian MC, McCabe MS, Korn EL, Abrams JS, Kaplan RS, Friedman MA. The National Cancer Institute audit of the National Surgical Adjuvant Breast and Bowel Project Protocol B-06. N Engl J Med 1995; 333:1469-74. [PMID: 7477148 DOI: 10.1056/nejm199511303332206] [Citation(s) in RCA: 52] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
BACKGROUND The National Surgical Adjuvant Breast and Bowel Project (NSABP) Protocol B-06, a clinical trial sponsored by the National Cancer Institute (NCI), has provided evidence of the value of lumpectomy and breast irradiation for treating women with breast cancer in an early stage. Publicity generated by the discovery that the study included fraudulent data on patients enrolled by St. Luc Hospital in Montreal aroused concern about the overall accuracy of the data and conclusions. To address this concern, the NCI conducted an audit of other participating institutions. METHODS In 1994, data on 1554 of the 1809 randomized patients (85.9 percent) enrolled by centers other than St. Luc Hospital were audited at 37 clinical sites in North America. The audit included data on eligibility, survival, disease-free survival, the length of time to a recurrence of cancer in the ipsilateral breast, and documentation of signed informed consent. RESULTS End points were assessed for all 1554 patients, and eligibility was assessed for 1507 patients; 47 patients were excluded because their forms were not complete or not returned. A total of 1429 patients had their eligibility status verified. Of a total of 7770 data points examined with respect to the number of positive nodes at base line, treatment characteristics, first events (excluding death), recurrence of cancer in the ipsilateral breast, and survival, 7577 (97.5 percent) were verified, 123 (1.6 percent) could not be verified, and 70 (0.9 percent) were discrepant with the NSABP file. Of the 1554 patients, 1340 (86.2 percent) had all audited items (including eligibility) verified, 69 (4.4 percent) had at least one discrepant item, and 113 (7.3 percent) had at least one unverified item (as a result of missing or incomplete data); 32 (2.1 percent) were not assessed for eligibility but had no other discrepant or unverifiable items. Written informed consent was documented for 1098 patients before surgery and 210 after surgery; no date appeared on the signed form for 137. The informed-consent status was not verified for 71 patients and could not be determined for 38. The rates of verification of end-point data and documentation of written informed consent were similar among the total-mastectomy group, the lumpectomy group, and the group treated by lumpectomy and breast irradiation. CONCLUSIONS The audit confirms the adequacy of the data on which the reanalysis of Protocol B-06 and the results after 12 years of follow-up are based.
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Affiliation(s)
- M C Christian
- Cancer Therapy Evaluation Program, National Cancer Institute, Rockville, MD 20892, USA
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45
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Lech JJ, Waddell WJ, Friedman MA, Johnson LR. Uptake, disposition, and persistence of acrylonitrile in rainbow trout. Fundam Appl Toxicol 1995; 27:291-4. [PMID: 8529826 DOI: 10.1006/faat.1995.1136] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The uptake and disposition of [2,3-14C]acrylonitrile-derived 14C were studied in rainbow trout by water exposure. Trout were exposed to [14C]ACN at 5.3 micrograms/liter and sampled at various times during a 24-hr uptake phase. After transfer to fresh water, fish were sampled to 72 hr for the estimation of elimination rates and the half-life of 14C. Throughout these experiments several fish were also sacrificed for whole-body autoradiography. The uptake of 14C in carcass and viscera began to level off at 24 hr and the apparent elimination studies, the 14C appeared to persist in both muscle and octanol-water partition coefficient (log p = -0.92). The t1/2 of 14C in muscle in two such experiments was calculated to be 117 and 102 hr. The autoradiographs of whole-body sections of exposed trout also revealed a slow loss of 14C from muscle. Muscle extracts prepared from exposed fish were essentially nondialyzable. When dialyzed muscle extract was analyzed for protein and 14C after SDS-PAGE electrophoresis, most of the 14C was associated with a single protein band with a mobility comparable to standards in the 10,000 Dalton range. These studies indicate that the long halflife of 14C seen in trout muscle may be due to covalent binding of 14C to a protein with a molecular weight of approximately 10,000 Daltons.
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46
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Blumenthal GM, Abdel-Rahman AA, Wilmarth KR, Friedman MA, Abou-Donia MB. Toxicokinetics of a single 50 mg/kg oral dose of [2,3-14C]acrylamide in White Leghorn hens. Fundam Appl Toxicol 1995; 27:149-53. [PMID: 7589925 DOI: 10.1006/faat.1995.1118] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
A single oral dose of [2,3-14C]acrylamide (50 mg/kg) was administered in water to adult white leghorn hens. Seven groups of three hens were euthanized between 2 and 120 hr after administration. Within 12 hr, the hens excreted 70% of the administered dose, and more than 99% within 48 hr. Blood, plasma, liver, and muscle contained the greatest percentage of administered dose at 4 hr after dosing. Less than 0.02% of the administered dose appeared in brain at any time. Radiolabel accumulated in the eggs, with 0.52% of the administered dose accumulated within 5 days. Binding of radiolabel to erythrocytes was minimal. Elimination of radiolabel from all tissues was biphasic. Terminal elimination half-lives for 14C were longer than 10 days, at which time less than 0.2% of the administered dose remains in the tissues. Distribution half-lives for 14C were longest for whole blood and shortest for kidney. Radioactivity in the blood and plasma reached a peak at between 4 and 12 hr. Most of this radioactivity was identified as acrylamide, which disappeared biexponentially with terminal elimination half-lives longer than 10 days. Distribution half-lives for acrylamide were longest in brain and shortest in whole blood. These results show that orally administered acrylamide is poorly absorbed and rapidly eliminated from hens and accumulates in their eggs in a nonextractable form.
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Affiliation(s)
- G M Blumenthal
- Department of Pharmacology, Duke University, Medical Center, Durham, North Carolina 27710, USA
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47
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Abrams JS, Vena DA, Baltz J, Adams J, Montello M, Christian M, Onetto N, Desmond-Hellmann S, Canetta R, Friedman MA. Paclitaxel activity in heavily pretreated breast cancer: a National Cancer Institute Treatment Referral Center trial. J Clin Oncol 1995; 13:2056-65. [PMID: 7543562 DOI: 10.1200/jco.1995.13.8.2056] [Citation(s) in RCA: 91] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
PURPOSE To provide paclitaxel, an investigational drug at the inception of this study, to women with chemotherapy-refractory metastatic breast cancer and to evaluate response and toxicity in these patients. PATIENTS AND METHODS Two hundred sixty-seven patients with progressive disease (PD) following at least two chemotherapy regimens for metastatic breast cancer and a contraindication to further doxorubicin treatment received paclitaxel either at 175 mg/m2 intravenously (IV) over 24 hours or at 135 mg/m2 if they had prior irradiation to 30% of marrow-bearing bone or a cumulative dose of mitomycin > or = 20 mg/m2. RESULTS In a subgroup of patients (n = 172) with measurable disease, four complete responses (CRs) and 36 partial responses (PRs) occurred, for an overall response rate of 23% (95% confidence interval [CI], 17% to 30%). No differences in response rates were noted according either to the number of prior chemotherapy regimens received or to whether patients were considered refractory to doxorubicin. The dose and schedule used in this trial resulted in febrile neutropenia in 45% of patients and a hospitalization rate of 49%. CONCLUSION Paclitaxel's activity in this multiinstitutional trial in heavily pretreated patients confirms the encouraging results attained in single-institution trials. Although at this dose and schedule paclitaxel may be considered too myelosuppressive for palliative care, supportive measures such as colony-stimulating factors and antibiotics were not used prophylactically. Current research efforts are focusing on whether paclitaxel's activity against breast cancer is dose- and/or schedule-dependent, and on what role it has in patients with less advanced disease.
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Affiliation(s)
- J S Abrams
- Division of Cancer Treatment, National Cancer Institute, Bethesda, MD 20892-7436, USA
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48
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Abstract
A lifetime oncogenicity study in Fischer 344 rats was conducted to accurately characterize the carcinogenic potency of acrylamide. Acrylamide was administered in drinking water throughout the 106-week study at concentrations required to provide a dose of 0, 0.1, 0.5, or 2.0 mg/kg/day to males or 0, 1.0, or 3.0 mg/kg/day to females. Complete necropsy and gross pathology examinations were performed on all study animals. Histopathology examinations were conducted on selected tissues of all high-dose and control animals. Selected tissues from intermediate and low-dose groups were subjected to histopathological examinations as required to clarify high- and control-dose group observations. There was no visual observation of neurotoxicity in any study animal but sciatic nerve degeneration was observed in the male and female high-dose groups. Increased mortality related to acrylamide was observed in the high-dose male group from Month 17 to the end of the study and in the high-dose females during Month 24. Mesotheliomas of the testicular tunic were significantly increased in the high-dose male group. The combined incidence of mammary gland adenocarcinomas and fibroadenomas was significantly increased in both acrylamide-dosed female groups. Males and females in the high-dose groups as well as females of the low-dose group had significantly (p < 0.001) increased thyroid follicular cell adenomas and adenocarcinomas. A variety of other tumor types observed with increased incidence in a previous acrylamide oncogenicity study (i.e., combined CNS glial neoplasms, papillomas of the oral cavity, adenomas of the clitoral gland, and uterine adenocarcinomas) were not observed to be present at increased incidence in this study. This study confirms previously described acrylamide induction of benign tumors of the thyroid and mammary glands as well as mesotheliomas of the testis. By using a larger number of animals with an unbalanced study design, this study showed that acrylamide did not induce glial tumors and demonstrated that the no-observable-effect level for scrotal mesotheliomas is 0.5 mg/kg. It also demonstrated that the increased incidence of mammary tumors was again within historical control ranges.
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Affiliation(s)
- M A Friedman
- Cytec Industries Incorporated, West Paterson, New Jersey 07424, USA
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49
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Abstract
Benzophenone-3 (BZ-3) is one of the UV-absorbing agents that has been used in industry and medicine for more than 30 years. Millions of consumers are exposed to benzophenones on a daily basis owing to the widespread use of these compounds in many of the products on the market, such as lipsticks, hair sprays, hair dyes, shampoo and detergent bars and sunscreen lotions. This study was performed to investigate the pharmacokinetics of BZ-3 after oral administration at 100 mg kg-1 body weight in male Sprague-Dawley rats. Absorption from the gastrointestinal tract was rapid because BZ-3 was detected in blood 5 min after administration. The peak plasma concentration (Cmax) was 25.6 +/- 4.6 micrograms ml-1 and the time of occurrence (tmax) was 3.0 +/- 0.4 h. The half-life of absorption of BZ-3 was 0.71 h. The elimination pattern was biphasic with alpha and beta half-lives of elimination of 0.88 and 15.90 h, respectively. The results of this study indicate the presence of strong binding between the plasma protein and BZ-3. Tissue distribution studies at 6 h indicate that the liver contained the highest concentration of free (58.9 +/- 23.8 micrograms) and total (free+bound or conjugated) BZ-3 (2087 +/- 60.1 micrograms), followed by kidney and testes, respectively. Urine and feces analysis indicate that urine was the major route of excretion, followed by feces. Further analysis of urine samples also indicates that conjugation of BZ-3 with glucuronic acid was the major systemic elimination route for the compound.
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Affiliation(s)
- A M Kadry
- Pharmacology and Toxicology Department, New Jersey Medical School, University of Medicine and Dentistry of New Jersey, Newark, USA
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50
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Reagan KE, Wilmarth KR, Friedman MA, Abou-Donia MB. In vitro calcium and calmodulin-dependent kinase-mediated phosphorylation of rat brain and spinal cord neurofilament proteins is increased by glycidamide administration. Brain Res 1995; 671:12-20. [PMID: 7728524 DOI: 10.1016/0006-8993(94)01288-s] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
This study was carried out to determine the action of glycidamide (2,3-epoxy-1-propanamide), a neurotoxic metabolite of acrylamide, on Ca2+/calmodulin (CaM)-dependent protein kinase phosphorylation of cytoskeletal proteins. Acrylamide has been shown to increase Ca2+/CaM-dependent phosphorylation of neurofilament (NF) triplet proteins and autophosphorylation of Ca2+/CaM-dependent protein kinase II (CaM kinase II; EC 2.7.1.37). A daily intraperitoneal dose of 0.7 mmol/kg b.wt. of glycidamide or deionized water was administered to male Sprague-Dawley rats. Animals were sacrificed when signs of severe neurotoxicity became apparent at 13-16 days of treatment. Axonal floatation was used to isolate neurofilaments (NFs) and endogenous kinases from brains and spinal cords of treated and control animals. Samples isolated from brain and spinal cord of glycidamide-treated animals showed increased in vitro Ca2+/CaM-dependent phosphorylation of endogenous and exogenous NF proteins and increased autophosphorylation of CaM kinase II when compared with controls. CaM binding to the alpha, beta, and beta' subunits of CaM kinase II and antibody binding to the alpha-subunit of CaM kinase II in brain supernatant isolates was increased as a result of glycidamide treatment. These results suggest that increased Ca2+/CaM-dependent phosphorylation of cytoskeletal proteins may be involved in the pathogenesis of glycidamide-induced neurotoxicity.
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Affiliation(s)
- K E Reagan
- Department of Pharmacology, Duke University Medical Center, Durham, NC 27710, USA
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